Road surface image-drawing system for vehicle

ABSTRACT

In this invention, letters that can be seen by a pedestrian (101) are drawn on an intersection (103). A mark (MM2) that can be seen by the driver of the host vehicle (C) is drawn on the road (104) between the intersection (103) and the host-vehicle (C). The shapes of the letters (MO4) are corrected in accordance with the positional relationship between the pedestrian (101) and the intersection (103). The shape of the mark (MM2) is corrected in accordance with the positional relationship between the driver of the host-vehicle (C) and the road (104).

This application is a Continuation of U.S. application Ser. No.15/509,259 filed Jul. 17, 2017, that is a National Stage Entry ofPCT/JP2015/075320 filed Sep. 7, 2015, that claims priority from JapaneseApplication No. 2014-181881 filed Sep. 8, 2014, each of which isincorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention relates to a road surface image-drawing systemwhich is mounted on a vehicle and draws information regarding thevehicle or the like on a road surface.

BACKGROUND ART

There is known a vehicle display system for notifying/warninginformation of a vehicle to a driver himself or other person such as apedestrian/oncoming vehicle by illuminating (drawing) a figure or acharacter or the like on a road surface. For example, a vehicle displaysystem disclosed in Patent Document 1 is configured to notify/warn theapproach of an own vehicle to other person trying to enter anintersection by displaying a warning mark of a figure on a road surfaceat the intersection.

CITATION LIST Patent Document

Patent Document 1: Japanese Patent Publication No. 2009-184428

DISCLOSURE OF INVENTION Problems to be Solved by Invention

However, the viewpoints of the driver of the own vehicle and otherperson receiving the warning are different from each other. Therefore,the display made by the system disclosed in Patent Document 1 may bedistorted to the driver even when it is appropriate for other personreceiving the warning. As a result, the driving comfort may be impaired.

The present invention aims to provide a suitable display to both adriver of a vehicle providing information such as a warning and otherperson receiving the information.

Means for Solving the Problems

In order to solve the above problem, one aspect of the present inventionmay provide a road surface image-drawing system mounted on a vehicle.The road surface image-drawing system includes:

an image-drawing device configured to draw a first display to be visibleto a driver of the vehicle at a first position and draw a second displayto be visible to a person other than the driver at a second positiondifferent from the first position, and

a control device configured to correct a shape of the first displayaccording to a positional relationship between the first position andthe driver and correct a shape of the second display according to apositional relationship between the second position and the person otherthan the driver.

For example, the first position and the second position are on a road.In this case, the first position may be on the road located between anintersection and the vehicle. The second position may be on theintersection. Alternatively, the first position may be on a windshieldof the vehicle.

According to such a configuration, the first display can be drawn so asto have a distortion-free shape, as seen from the driver of the vehicleon which the system is mounted. On the other hand, the second displaycan be drawn so as to have a distortion-free shape, as seen from theperson other than the driver. Accordingly, it is possible to provide adisplay including information such as a warning in a suitable manner toboth the driver of the vehicle who provides the information and theperson who receives the information. Particularly, the driver who viewsthe first display can continue driving without diverting his attentionto the second display.

It is desirable that the information included in the first display andthe information included in the second display are related to eachother. For example, the first display may include information or warningnotifying the approach of other person to the driver. On the other hand,the second display may include information or warning notifying theapproach of the vehicle to the other person. That is, the first displayand the second display which are related to each other for the purposeof avoiding collision between the vehicle and the other person may bepresented in a manner corresponding to the situation of each of thedriver of the vehicle and the other person. Therefore, it is possible toproperly call attention of both the driver and the other person.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a front view showing a headlamp device including a roadsurface image-drawing system according to one embodiment.

FIG. 2 is a longitudinal sectional view showing the headlamp device.

FIG. 3A is a view showing a configuration of an image-drawing device inthe road surface image-drawing system.

FIG. 3B is a view showing a configuration of the image-drawing device inthe road surface image-drawing system.

FIG. 4 is a functional block diagram showing a configuration of acontrol device in the road surface image-drawing system.

FIG. 5 is a view for explaining an image-drawing operation by the roadsurface image-drawing system.

FIG. 6 is a flow chart showing a control process executed by the roadsurface image-drawing system.

FIG. 7 is a flow chart showing a control process executed by the roadsurface image-drawing system.

FIG. 8A is a view showing an example of the image-drawing operationexecuted by the road surface image-drawing system.

FIG. 8B is a view showing an example of the image-drawing operationexecuted by the road surface image-drawing system.

FIG. 8C is a view showing an example of the image-drawing operationexecuted by the road surface image-drawing system.

FIG. 8D is a view showing an example of the image-drawing operationexecuted by the road surface image-drawing system.

FIG. 9 is a view showing another example of the image-drawing operationexecuted by the road surface image-drawing system.

FIG. 10 is a view for explaining a modified example of the road surfaceimage-drawing system.

EMBODIMENT FOR CARRYING OUT INVENTION

Hereinafter, examples of preferred embodiments will be described indetail with reference to the accompanying figures. In each figure usedin the following description, the scale is appropriately changed inorder to make each member have recognizable size. The “right” and “left”used in the following description indicate the left and right directionsas seen from a driver's seat.

FIG. 1 is a front view of a headlamp device 1 according to oneembodiment. FIG. 2 shows a longitudinal section of the headlamp device1, when seeing a line II-II in FIG. 1 from an arrow direction. Theheadlamp device 1 is a right headlamp device mounted on the right frontpart of a vehicle. Although not shown, a left headlamp device mounted onthe left front part of the vehicle has a configurationbilaterally-symmetric to the headlamp device 1 shown in FIG. 1.

The headlamp device 1 includes a housing 2 and a translucent cover 3.The housing 2 has an opening portion. The translucent cover 3 is formedof a light-transmitting resin or glass or the like. The translucentcover 3 is attached to the opening portion of the housing 2 and definesa lamp chamber.

The headlamp device 1 further includes a high-beam light source unit 5and a low-beam light source unit 6. The high-beam light source unit 5and the low-beam light source unit 6 are accommodated in the lampchamber. The high-beam light source unit 5 in the present example is areflection type and is configured to illuminate the front of the vehiclewith a high-beam light distribution pattern. The low-beam light sourceunit 6 in the present example is a projector type and is configured toilluminate the front of the vehicle with a low-beam light distributionpattern. The types of the high-beam light source unit 5 and the low-beamlight source unit 6 can be appropriately determined, so long as adesired illumination can be obtained.

The headlamp device 1 includes a bracket 4 and aiming screws 14. Thebracket 4 is accommodated in the lamp chamber. The high-beam lightsource unit 5 and the low-beam light source unit 6 are supported by thebracket 4. The bracket 4 is fixed to the housing 2 via the aiming screws14. The aiming screws 14 are provided at three corner portions of thebracket 4. By operating the aiming screws 14 to rotate, the direction ofan optical axis of the headlamp device 1 can be adjusted in an up-downdirection and a left-right direction.

The headlamp device 1 includes an extension 12. The extension 12 coverseach component disposed in the lamp chamber so that these componentscannot be visible from the outside while allowing the passage of thelight emitted from the high-beam light source unit 5 and the low-beamlight source unit 6.

The headlamp device 1 includes a road surface image-drawing system 7.The road surface image-drawing system 7 is accommodated in the lampchamber. The road surface image-drawing system 7 includes animage-drawing device 8 and a control device 9. The image-drawing device8 includes a laser light source unit 10 and a scanning mechanism 11. Thecontrol device 9 is fixed to the housing 2.

FIG. 3A schematically shows a configuration of the laser light sourceunit 10. The laser light source unit 10 includes a first light source15, a second light source 16, a third light source 17 and a supportstand 18. The first light source 15, the second light source 16 and thethird light source 17 are supported on the support stand 18.

The first light source 15 is configured to emit a red laser light. Thesecond light source 16 is configured to emit a green laser light. Thethird light source 17 is configured to emit a blue laser light. In thepresent embodiment, each of the first light source 15, the second lightsource 16 and the third light source 17 is a laser diode.

The laser light source unit 10 includes a first condensing lens 20, asecond condensing lens 21, a third condensing lens 22, a first dichroicmirror 25, a second dichroic mirror 26 and a third dichroic mirror 27.The red laser light emitted from the first light source 15 is condensedby the first condensing lens 20 and is incident on the first dichroicmirror 25. The green laser light emitted from the second light source 16is condensed by the second condensing lens 21 and is incident on thesecond dichroic mirror 26. The blue laser light emitted from the thirdlight source 17 is condensed by the third condensing lens 22 and isincident on the third dichroic mirror 27.

The laser light source unit 10 includes a condensing lens 19. The lightreflected by the first dichroic mirror 25, the second dichroic mirror 26and the third dichroic mirror 27 passes through the condensing lens 19as an output light B2. By controlling the turn on/off of the first lightsource 15, the second light source 16 and the third light source 17, theoutput light B2 can be a monochromatic light, a mixed color light or awhite light.

The laser light source unit 10 includes a monitor 28. The monitor 28 isconfigured to be able to monitor the intensity of the red laser light,the green laser light, the blue laser light and the output light B2.Further, the monitor 28 is configured to be able to control theintensity of the red laser light emitted from the first light source 15,the intensity of the green laser light emitted from the second lightsource 16 and the intensity of the blue laser light emitted from thethird light source 17.

FIG. 3B shows a configuration of the scanning mechanism 11. The scanningmechanism 11 is configured as an MEMS (Micro Electro Mechanical Systems)mirror. The scanning mechanism 11 includes a base part 37, a firstpivoting body 38, a second pivoting body 39, a pair of first torsionbars 40 and a pair of second torsion bars 41.

The base part 37 has a first opening portion. The first pivoting body 38is disposed in the opening portion and is supported on the base part 37via the pair of first torsion bars 40. The first pivoting body 38 ispivotable in a left-right (horizontal) direction.

The first pivoting body 38 has a second opening portion. The secondpivoting body 39 is disposed in the second opening portion and issupported on the first pivoting body 38 via the pair of second torsionbars 41. The second pivoting body 39 is pivotable in an up-down(vertical) direction. The second pivoting body 39 has a reflectivesurface 36.

The scanning mechanism 11 includes a pair of first permanent magnets 42,a pair of second permanent magnets 43 and a terminal portion 44.

The pair of first torsion bars 40 is disposed between the pair of firstpermanent magnets 42. The direction of a straight line connecting thepair of first permanent magnets 42 is orthogonal to the extendingdirection of the pair of first torsion bars 40.

The pair of second torsion bars 41 is disposed between the pair ofsecond permanent magnets 43. The direction of a straight line connectingthe pair of second permanent magnets 43 is orthogonal to the extendingdirection of the pair of second torsion bars 41.

The first pivoting body 38 includes a first coil (not shown). The secondpivoting body 39 includes a second coil (not shown). The first coil andthe second coil are electrically connected to the control device 9 viathe terminal portion 44.

As shown in FIG. 2, the laser light source unit 10 is fixed to thebracket 4 so that the output light B2 is emitted downward. The scanningmechanism 11 is disposed so that the output light B2 is reflected to thefront of the headlamp device 1 by the reflective surface 36.

As shown in FIG. 4, the scanning mechanism 11 includes a scanningactuator 58. Specifically, the scanning actuator 58 is composed of thepair of first permanent magnets 42, the pair of second permanent magnets43, the first coil and the second coil. When the magnitude and directionof current flowing in the first coil and the second coil are changed,the pivoting direction and amount of the first pivoting body 38 and thesecond pivoting body 39 are changed. In this way, the direction of thereflective surface 36 is changed in the up-down direction and theleft-right direction.

As shown in FIG. 4, the control device 9 is communicatively connected toa vehicle speed sensor 60, a steering angle sensor 61, an accelerationsensor 62, a direction indicator detection sensor 63, a brake sensor 64,a GPS 65, a navigation system 66, an on-vehicle camera 67, a precedingvehicle detection sensor 68, a human body detection sensor 69, anilluminance sensor 70, an external system 71, and an image processingdevice 72.

The vehicle speed sensor 60 is configured to detect a travellingdistance and a vehicle speed by the rotation of vehicle wheels. Thesteering angle sensor 61 is configured to detect a steering angle of asteering wheel. The acceleration sensor 62 is configured to detect anoperating amount of an accelerator. The direction indicator detectionsensor 63 is configured to detect a switch operation of a directionindicator. The brake system 64 is configured to detect an operatingamount of a brake. The navigation system 66 is configured to detect acurrent position of the own vehicle and perform a route guidance to thedestination based on a data received from the GPS 65 and a map data. Theon-vehicle camera 67 is configured to capture and record an image infront of the own vehicle. The preceding vehicle detection sensor 68 isconfigured to detect a distance to a preceding vehicle and a relativespeed by using millimeter waves or the like. The human body detectionsensor 69 is configured to detect a human body located in front of theown vehicle by using infrared rays or the like. The illuminance sensor70 is configured to detect an illuminance of the surrounding environmentof the own vehicle by using the photoelectric effect. As an example ofthe external system 71, an intersection camera or a monitoring camerainstalled at intersection signals can be exemplified. The imageprocessing device 72 is configured to perform an image processing on animage data acquired by the on-vehicle camera 67 and the external system71 and thus to recognize a specific object.

The control device 9 includes a lamp ECU 51, a ROM 52 and a RAM 53. Thelamp ECU 51 executes various programs stored in advance in the ROM 52 onthe RAM 53, thereby generating various control signals.

The lamp ECU 51 includes an own vehicle data acquisition unit 83. Theown vehicle data acquisition unit 83 is configured to receive data fromat least one of the vehicle speed sensor 60, the steering angle sensor61, the acceleration sensor 62, the direction indicator detection sensor63, the brake sensor 64, the GPS 65, the navigation system 66 and theilluminance sensor 70 and to acquire information on the travellingconditions including the current position of the own vehicle and thesurrounding environments.

The lamp ECU 51 includes a travelling environment determination unit 84.The travelling environment determination unit 84 is configured todetermine whether image-drawing by the image-drawing device 8 ispossible based on the information on the travelling conditions andsurrounding environments of the own vehicle acquired by the own vehicledata acquisition unit 83. When it is determined that the image-drawingis possible, the travelling environment determination unit 84 isconfigured to permit the image-drawing by the image-drawing device 8.When it is determined that the image-drawing is not possible, thetravelling environment determination unit 84 is configured to prohibitthe image-drawing by the image-drawing device 8.

For example, when the own vehicle is stopped, the travelling environmentdetermination unit 84 determines that the image-drawing is unnecessary,thereby prohibiting the image-drawing. When the own vehicle istravelling at a speed within a predetermined range, the travellingenvironment determination unit 84 permits the image-drawing. When thespeed of the own vehicle exceeds a predetermined value, the travellingenvironment determination unit 84 determines that effectiveimage-drawing cannot be performed, thereby prohibiting theimage-drawing.

As another example, when it is determined that the own vehicle istravelling around a curve to the extent that it cannot perform theeffective image-drawing, the travelling environment determination unit84 prohibits the image-drawing. When it is determined that the ownvehicle is travelling on the priority road, the travelling environmentdetermination unit 84 permits the image-drawing. When it is determinedthat the own vehicle is in an environment in which the image-drawingcannot be effectively performed on the road surface due to a tunnel orrainy weather or the like, the travelling environment determination unit84 prohibits the image-drawing. When the presence of a signal isdetected, the possibility of the run-out by other person is low, andthus, the travelling environment determination unit 84 may determinethat the image-drawing is unnecessary in order to make driving easier.

The lamp ECU 51 includes an other vehicle data acquisition unit 85. Theother vehicle data acquisition unit 85 is configured to acquire datafrom at least one of the on-vehicle camera 67, the preceding vehicledetection sensor 68 and the external system 71 and to acquireinformation on a distance to the other vehicle and a relative speed.

The lamp ECU 51 includes an other vehicle determination unit 86. Theother vehicle determination unit 86 is configured to determine whetherthe image-drawing by the image-drawing device 8 is possible based on theinformation acquired by the other vehicle data acquisition unit 85 andto determine whether the image-drawing by the image-drawing device 8 ispossible. When it is determined that the image-drawing is possible, theother vehicle determination unit 86 is configured to permit theimage-drawing by the image-drawing device 8. When it is determined thatthe image-drawing is not possible, the other vehicle determination unit86 is configured to prohibit the image-drawing by the image-drawingdevice 8.

For example, when it is determined that a preceding vehicle is notpresent, the other vehicle determination unit 86 permits theimage-drawing. When it is determined that a preceding vehicle ispresent, the other vehicle determination unit 86 permits theimage-drawing. When it is determined that an image-drawableinter-vehicle distance is secured even if a preceding vehicle ispresent, the other vehicle determination unit 86 permits theimage-drawing. When it is determined that effective image-drawing cannotbe performed in consideration of the relative speed even if theimage-drawable inter-vehicle distance is secured, the other vehicledetermination unit 86 prohibits the image-drawing. When it is determinedthat the image-drawing can be performed on the road surface on the sideof the preceding vehicle even if the inter-vehicle distance is too shortto perform effective image-drawing, the other vehicle determination unit86 permits the image-drawing.

The lamp ECU 51 includes a pedestrian data acquisition unit 87. Thepedestrian data acquisition unit 87 is configured to acquire data fromat least one of the on-vehicle camera 67, the human body detectionsensor 69 and the external system 71 and to acquire information on thepresence of a pedestrian (including a bicycle) and the state (travelingdirection, etc.) thereof.

The lamp ECU 51 includes a pedestrian determination unit 88. Thepedestrian determination unit 88 is configured to determine thepresence/absence of a pedestrian based on the information acquired bythe pedestrian data acquisition unit 87.

The lamp ECU 51 includes an intersection data acquisition unit 89. Theintersection data acquisition unit 89 is configured to acquire data fromat least one of the on-vehicle camera 67 and the navigation system 66and thus to acquire information on the presence of an intersection andthe situations (the presence/absence of a signal the presence/absence ofa road illumination, the presence of obstacles around the intersection,etc.) of the intersection.

The lamp ECU 51 includes an intersection determination unit 90. Theintersection determination unit 90 is configured to determine thepresence/absence of an intersection based on the information acquired bythe intersection data acquisition unit 89. The intersectiondetermination unit 90 can be also configured to determine whether it isan intersection in which the necessity of performing the image-drawingis high, based on the information on the situations of the intersectionacquired by the intersection data acquisition unit 89. When it isdetermined that an intersection is present (when it is determined thatthe notification or warning by the image-drawing is necessary inconsideration of the situations of the intersection), the intersectiondetermination unit 90 permits the image-drawing in the normal mode.

The lamp ECU 51 includes a pedestrian risk determination unit 91. Thepedestrian risk determination unit 91 is configured to acquire adistance (hereinafter, referred to as a “pedestrian distance”) to apedestrian based on the position, travelling direction and walking speedor the like of a pedestrian. Further, the pedestrian risk determinationunit 91 is configured to acquire a braking distance of the own vehiclebased on the position, travelling direction and driving speed or thelike of the own vehicle. When the pedestrian distance is equal to orgreater than the braking distance, the pedestrian risk determinationunit 91 permits the image-drawing in the normal mode. On the other hand,when the pedestrian distance is less than the braking distance, there isa danger of collision, and thus, the pedestrian risk determination unit91 permits the image-drawing in the emergency mode.

The lamp ECU 51 includes a display content determination unit 92. Thedisplay content determination unit 92 is configured to determine displaycontents when the image-drawing is permitted by the travellingenvironment determination unit 84, the other vehicle determination unit86, the pedestrian determination unit 88 or the intersectiondetermination unit 90). Specifically, the display content determinationunit 92 is configured to determine a figure or a character to be drawntogether with its display form in accordance with the determinedsituations (including a risk). Further, the display contentdetermination unit 92 is configured to control the image-drawing device8, thereby image-drawing the display contents.

The lamp ECU 51 includes a laser light source control unit 81. The laserlight source control unit 81 is configured to control the turn on/offand emission light intensity (i.e., color and brightness of output lightB2) of each of the first light source 15, the second light source 16 andthe third light source 17, based on the display contents determined bythe display content determination unit 92.

The lamp ECU 51 includes an actuator control unit 82. The actuatorcontrol unit 82 is configured to control an operation of the scanningactuator 58 based on the display contents determined by the displaycontent determination unit 92.

Therefore, through the control by the laser light source control unit 81and the actuator control unit 82, the output light B2 emitted from thelaser light source unit 10 is reflected in a desired direction by thescanning mechanism 11. In this way, the image-drawing device 8 causesdesired display contents to be drawn on a road surface located in frontof the headlamp device 1 by using the output light B2.

Next, a road surface image-drawing operation performed by the roadsurface image-drawing system 7 will be described with reference to FIG.5. FIG. 5 shows a virtual vertical screen positioned in front of theheadlamp device 1. A reference numeral “CR” indicates a travelling laneof the own vehicle.

The scanning mechanism 11 of the image-drawing device 8 is configured sothat the output light B2 can scan the inside of a rectangular scanningarea SA shown in FIG. 5. The scanning area SA is preferably set suchthat it can cover a road shoulder of the travelling lane CR, a laneadjacent to the travelling lane CR and the range of 5 m to 50 m in frontof the own vehicle. For example, it is preferable that the scanning areaSA is set to the left-right direction range of −1° to −8° on ahorizontal line H-H shown in FIG. 5 and the up-down direction range of20° to −20° on a vertical line V-V shown in FIG. 5.

The control device 9 controls an operation of the image-drawing device 8to cause a display MM for a driver and a display MO for other person tobe drawn at different places in the scanning area SA, respectively. Thedisplay MM (an example of the first display) for the driver is a displayto be visible to the driver of the own vehicle. The display MO (anexample of the second display) for the other person is a display to bevisible to a person other than the driver of the own vehicle, such as apedestrian or a driver of a preceding vehicle. The display MM for thedriver and the display MO for the other person are based on the displaycontents determined by the display content determination unit 92 of thecontrol device 9. The display MM for the driver and the display MO forthe other person may be drawn in a partially overlapping manner, as longas each of them includes a different point in the scanning area SA.

The scanning mechanism 11 of the image-drawing device 8 changes theorientation of the reflective surface 36 based on a control signal fromthe actuator control unit 82 of the control device 9. In this way, thescanning point can be horizontally reciprocated in the scanning area SAwhile shifting its position in the vertical direction by dl. A referencenumeral “SI” in FIG. 5 indicates a movement trajectory of the scanningpoint.

When the scanning point reaches the image-drawing positions of thedisplay MM for the driver and the display MO for the other person, atleast one of the first light source 15, the second light source 16 andthe third light source 17 is turned on (pan indicated by a solid line,out of the movement trajectory SI of the scanning point shown in FIG. 5)on the basis of the control signal from the laser light source controlunit 81 of the control device 9. In this way, the display MM for thedriver and the display MO for the other person are drawn at desiredpositions by using the output light B2. When the scanning point islocated at positions other than the drawing positions of the display MMfor the driver and the display MO for the other person, all of the firstlight source 15, the second light source 16 and the third light source17 are turned off (part indicated by a broken line, out of the movementtrajectory SI of the scanning point shown in FIG. 5).

The road surface image-drawing system 7 repeatedly performs the scanningof one cycle shown in FIG. 5 and appropriately determines the drawingpositions of the display MM for the driver and the display MO for theother person in each cycle. In this way, the display MM for the driverand the display MO for the other person with an arbitrary shape can becontinuously or intermittently displayed in the scanning area SA. Theroad surface image-drawing system 7 appropriately changes the drawingpositions of the display MM for the driver and the display MO for theother person in each cycle. In this way, the display form of the displayMM for the driver and the display MO for the other person can bedynamically changed.

Next, an operation of the road surface image-drawing system 7 will bedescribed in more detail with reference to the flow charts shown inFIGS. 6 and 7.

When the road surface image-drawing system 7 is activated at apredetermined timing, information on the travelling conditions andsurrounding environments of the own vehicle is acquired by the ownvehicle data acquisition unit 83 (Step S10). Then, when it is determinedby the travelling environment determination unit 84 based on theinformation that the image-drawing is possible (Step S11: YES), theprocess proceeds to Step S12. When it is determined by the travellingenvironment determination unit 84 that the image-drawing is not possible(Step S11: NO), the image-drawing is not performed.

Subsequently, information on a distance to a preceding vehicle and arelative speed is acquired by the other vehicle data acquisition unit 85(Step S12). Then, when it is determined by the other vehicledetermination unit 86 based on the information that image-drawing ispossible or partial image-drawing is possible (Step S13: YES), theprocess proceeds to Step S14. When it is determined by the other vehicledetermination unit 86 that the image-drawing is not possible (Step S13:NO), the image-drawing is not performed.

Subsequently, information on a pedestrian is acquired by the pedestriandata acquisition unit 87 (Step S14). Then, when it is determined by thepedestrian determination unit 88 based on the information that apedestrian is present (Step S15: YES), the process proceeds to Step S17.When it is determined by the pedestrian determination unit 88 that apedestrian is not present (Step S15: NO), the process proceeds to StepS16.

In Step S16, information on an intersection is acquired by theintersection data acquisition unit 89. When it is determined by theintersection determination unit 90 based on the information that anintersection is present (Step S16: YES), an instruction to performimage-drawing in the normal mode is issued and the process proceeds toStep S18. When it is determined by the intersection determination unit90 that an intersection is not present (Step S16: NO), image-drawing isnot performed and the process is repeated from the Step S10 again.

In Step S17, a pedestrian distance and a braking distance are acquiredby the pedestrian risk determination unit 91. When the pedestriandistance is equal to or greater than the braking distance, aninstruction to perform image-drawing in the normal mode is issued andthe process proceeds to Step S18. When the pedestrian distance is lessthan the braking distance, an instruction to perform image-drawing inthe emergency mode is issued and the process proceeds to Step S18.

The Step S18 is performed when image-drawing permission is made inprevious Step S11 and Step S13 and image-drawing permission is made inStep S15 or S16. In Step S18. “display contents” are determined by thedisplay content determination unit 92. FIG. 7 shows details of theprocess performed by the display content determination unit 92 in StepS18.

In Step S21, a figure or character or the like to be drawn as thedisplay MO for the other person and an image-drawing area thereof and afigure or character or the like to be drawn as the display MM for thedriver and an image-drawing area thereof are determined in accordancewith the situations corresponding to the data acquired in previous steps(Step S10 to Step S16).

When the display MO for the other person is presented to a pedestrian,the display content determination unit 92 performs a trapezoidaldistortion correction on the figure or character or the like to be drawnas the display MO for the other person so that a distortion-free shapeis obtained as seen from the detected pedestrian. When the display MOfor the other person is presented to a driver of a preceding vehicle,the display content determination unit 92 performs a trapezoidaldistortion correction on the figure or character or the like to be drawnas the display MO for the other person so that a distortion-free shapeis obtained as seen from the driver of the preceding vehicle detected.In other words, the display content determination unit 92 corrects theshape of the display MO for the other person based on a positionalrelationship between the detected other person (person other than thedriver of the own vehicle) and the image-drawing area of the display MOfor the other person.

Further, the display content determination unit 92 performs atrapezoidal distortion correction on the figure or character or the liketo be drawn as the display MM for the driver so that a distortion-freeshape is obtained as seen from the driver of the own vehicle. Thetrapezoidal distortion correction is performed on the basis of aninstallation height of the headlamp device 1 or a distance to theimage-drawing area or the like. In other words, the display contentdetermination unit 92 corrects the shape of the display MM for thedriver based on a positional relationship between the driver of the ownvehicle and the drawing area of the display MM for the driver.

Subsequently, the display content determination unit 92 sequentiallydetermines whether an instruction to perform the image-drawing in thenormal mode in previous steps (Step S16 to Step S17) is issued (StepS22) and whether an instruction to perform the image-drawing in theemergency mode is issued (Step S24). When the instruction to perform theimage-drawing is not issued (Step S22 and Step S23: NO), image-drawingis not performed and the process is repeated from the Step S10 again.

When the instruction to perform the image-drawing in the normal mode isissued (Step S22: YES), the image-drawing is performed such that thefigure or character or the like determined in the image-drawing areadetermined in Step S21 is constantly displayed or is displayed with slowblinking (Step S23).

When the instruction to perform the image-drawing in the emergency modeis issued (Step S24: YES), the image-drawing is performed such that thefigure or character or the like determined in the image-drawing areadetermined in Step S21 is displayed with fast blinking. The blinkingfrequency of the display in the emergency mode image-drawing is fasterthan that of the display in the normal mode image-drawing. The blinkingfrequency of the display in the emergency mode image-drawing is, forexample, 1 Hz.

Subsequently, it is determined whether the instruction to perform theimage-drawing in the emergency mode is continued for a predeterminedtime or more (Step S26). When it is determined that the instruction toperform the image-drawing in the emergency mode is continued for thepredetermined time or more (Step S26: YES), the blinking frequency ischanged so as to rise (Step S27). For example, when the initial fastblinking (1 Hz) is continued for the predetermined time or more, theblinking frequency is increased by 1 Hz. For example, the image-drawingis performed such that this processing is repeated until the blinkingfrequency becomes 4 Hz. This is repeatedly performed, for example, up to4 Hz. When the instruction to perform the image-drawing in the emergencymode is not continued for the predetermined time or more (Step S26: NO),the image-drawing in the initial fast blinking state is continued.

A preferred example of display by the road surface image-drawing system7 having the above configuration will be described with reference toFIGS. 8A to 10.

FIGS. 8A to 8D show an example where the road surface image-drawing isperformed at an intersection by the road surface image-drawing system 7.FIGS. 8A to 8D schematically show a state of an intersection 103 seenfrom above. In the present example, the travelling environmentdetermination unit 84 determines that the travelling conditions and thesurrounding environments are in the state of capable of performing theimage-drawing (Step S11: YES). The other vehicle data acquisition unit85 determines that an image-drawable distance (e.g., 50 m) is securedalthough a preceding vehicle 102 is present (Step S13: YES). Thepedestrian data acquisition unit 87 determines that a pedestrian is notpresent (Step S15: NO). The intersection determination unit 90determines that an intersection is present (e.g., at 30 m) in front ofthe own vehicle C (Step S16: YES). Therefore, an instruction to performthe image-drawing in the normal mode is issued.

Based on these conditions, display contents are determined (Step S21).Specifically, it is determined that a “rectilinear arrow” for informingthe other person that the own vehicle C goes straight through theintersection 103 is drawn at the intersection 103 (an example of thesecond position) as the display for the other person. Further, it isdetermined that a “rectilinear arrow” for informing the driver of theown vehicle C of the same information as the display for the otherperson is drawn on a road 104 (an example of the first position) as thedisplay for the driver. The road 104 is positioned between the ownvehicle C and the intersection 103.

As shown in FIG. 8A, a straight arrow MO1 as the display for the otherperson is drawn in a left end region of the intersection 103. The shapeof the straight arrow MO1 is corrected so that it can be seen withoutdistortion, as viewed from a driver of other vehicle or a pedestrian whois likely to enter the intersection 103 from the left side.

As shown in FIG. 8B, a straight arrow MO2 as the display for the otherperson is drawn in a right end region of the intersection 103. The shapeof the straight arrow MO2 is corrected so that it can be seen withoutdistortion, as viewed from a driver of other vehicle or a pedestrian whois likely to enter the intersection 103 from the right side.

As shown in FIG. 8C, a straight arrow MO3 as the display for the otherperson is drawn in a front end region of the intersection 103. The shapeof the straight arrow MO3 is corrected so that it can be seen withoutdistortion, as viewed from a driver of other vehicle or a pedestrian whois likely to enter the intersection 103 from the front side.

As shown in FIG. 8D, a straight arrow MM1 as the display for the driveris drawn on the road 104. The shape of the straight arrow MM1 iscorrected so that it can be seen without distortion, as viewed from thedriver of the own vehicle C.

According to these displays, the straight arrows MO1, MO2, MO3 as thedisplays for the other person are presented without distortion to theother person approaching the intersection 103. Therefore, the otherperson can accurately recognize the fact that the own vehicle C isapproaching the intersection 103. On the other hand, the display for thedriver related to the display for the other person is presented withoutdistortion to the driver of the own vehicle C. Therefore, the driver ofthe own vehicle C can continue driving without diverting his attentionto the display for the other person.

The straight arrows MO1, MO2, MO3 as the displays for the other personare preferably displayed to be large in the full width of theintersection 103 in order to enhance the effect of calling attention. Onthe other hand, the straight arrow MM1 as the display for the driver ispreferably spot-displayed on the tip of line of sight of the driver ofthe own vehicle C. The line of sight of the driver is detected by, forexample, an eye camera connected to the lamp ECU 51.

The timing at which the straight arrows MO1, MO2, MO3 as the displaysfor the other person and the straight arrow MM1 as the display for thedriver are drawn can be appropriately determined. These displays may besequentially drawn one by one, or, at least two of these displays may besimultaneously drawn when the image-drawing areas thereof are notoverlapped. When the displays are sequentially drawn, the image-drawingtime of each display and the number of scanning cycles described withreference to FIG. 5 can be appropriately determined. For example, thedisplay to be drawn per one scanning cycle may be switched or a specificdisplay may be drawn over a plurality of scanning cycles. When thedisplays are sequentially drawn, the order in which each display isdrawn can be appropriately determined.

FIG. 9 shows another example in which the road surface image-drawing isperformed at the intersection by the road surface image-drawing system7. FIG. 9 schematically shows a state of the intersection 103 seen fromabove. In this example, the pedestrian determination unit 88 determinesthat a pedestrian 101 tying to enter the intersection 103 is present(Step S15: YES). The pedestrian risk determination unit 91 determinesthat the distance (e.g., 20 m) between the own vehicle C and thepedestrian 101 is equal to or greater than the braking distance (e.g.,13 m) of the own vehicle C (Step S17). Therefore, an instruction toperform the image-drawing in the normal mode is issued.

Based on these conditions, display contents are determined (Step S21).Specifically, it is determined that the character of “STOP” for urgingnot to enter the intersection 103 is drawn at the intersection 103 asthe display for the other person. Further, it is determined that a markfor informing the driver of the own vehicle C of the presence of thepedestrian 101 trying to enter the intersection 103 is drawn on the road104 as the display for the driver.

As shown in FIG. 9, a character MO4 (an example of the second display)of “STOP” as the display for the other person is drawn at theintersection 103 (an example of the second position). The shape of thecharacter M04 is corrected so that it can be seen without distortion, asviewed from the pedestrian 101 trying to enter the intersection 103 fromthe left side.

On the other hand, a mark MM2 (an example of the first display)indicating the presence of the pedestrian 101, the pedestrian distance(20 m) and the approaching direction to the intersection 103 is drawn onthe road 104 (an example of the first position) as the display for thedriver. The shape of the mark MM2 is corrected so that it can be seenwithout distortion, as viewed from the driver of the own vehicle C.

According to these displays, the character MO4 as the display for theother person is presented without distortion to the pedestrian 101approaching the intersection 103. Therefore, the pedestrian 101 canaccurately recognize the fact that the own vehicle C is approaching theintersection 103. On the other hand, the mark MM2 related to the displayfor the other person is presented without distortion to the driver ofthe own vehicle C. Therefore, the driver of the own vehicle C cancontinue driving without diverting his attention to the display for theother person and can accurately recognize the fact that the pedestrian101 is approaching the intersection 103.

Further, in the present example, the character MO4 as the display forthe other person is intended to inform the pedestrian 101 of theapproach of the own vehicle C to the intersection 103 and the mark MM2as the display for the driver is intended to inform the driver of theown vehicle C of the approach of the pedestrian 101 to the intersection103. That is, information for avoiding collision at the intersection 103is presented in a manner corresponding to the situation of each of thedriver of the own vehicle C and the pedestrian 101. Therefore, it ispossible to properly call attention of both the driver of the ownvehicle C and the pedestrian 101.

A case in which the pedestrian 101 overlooks the character MO4 as thedisplay for the other person and further approaches the intersection 103from the situation shown in FIG. 9 will be described as an example.

The pedestrian risk determination unit 91 determines that the distance(e.g., 10 m) to the pedestrian 101 is less than the braking distance(e.g., 13 m) of the own vehicle C (Step S17). Therefore, an instructionto perform the image-drawing in the emergency mode is issued.

Based on these conditions, display contents are determined (Step S21).Specifically, it is determined that the character MO4 and the mark MM2are blinked at a high speed. Display contents with higher warning thanthe character M04 and the mark MM2 may be selected.

Based on the determined display contents, the image-drawing in theemergency mode is performed (Steps S24 and S25). In the case where theinstruction to perform the image-drawing in the emergency mode iscontinued for a predetermined time (e.g., one second) (Step S26: YES),the blinking frequency is increased (Step S27).

The above description is intended to facilitate the understanding of thepresent invention and does not limit the present invention. It isobvious that the present invention can be changed/enhanced withoutdeparting from the spirit thereof and equivalents thereof are includedin the present invention.

The forms of the displays MO1, MO2, MO3, MO4 for the other person arenot limited to the examples described for the above embodiment. Anysuitable form can be adopted according to the situations, so long as itcan notify the other person of the approach or behavior of the ownvehicle. For example, more detailed information such as an operation ofa brake or a steering wheel by the driver of the own vehicle,acceleration of the own vehicle and driver's attribute information (sexor whether he is a child or an elderly person) may be included in thedisplay for the other person. Alternatively, when the own vehicle dataacquisition unit 83 determines that the driver of the own vehiclerecognizes the other person such as a pedestrian based on the brakeoperation, travelling speed and information from the eye camera or thelike, the content notifying the fact may be included in the display forthe other person.

The forms of the displays MM1, MM2 for the driver are not limited to theexamples described for the above embodiment. Any suitable form can beadopted according to the situations, so long as it can notify the driverof the own vehicle of the presence or behavior of the other person. Forexample, more detailed information such as the number and attribute (sexor whether he is a child or an elderly person) of the pedestrianacquired by the pedestrian data acquisition unit 87 may be included inthe display for the driver. Alternatively, when the pedestrian dataacquisition unit 87 determines that the pedestrian recognizes the ownvehicle, the content notifying the fact may be included in the displayfor the driver.

The display for the other person and the display for the driver arebased on mutually related information. In order to emphasize thisrelevance, a line connecting the display for the other person and thedisplay for the driver may be drawn.

A region that looks relatively dark may be drawn so as to border thedisplay for the other person and the display for the driver.Specifically, the region may be drawn with a color which has brightnessor saturation lower than the colors of the display for the other personand the display for the driver or a color which makes the colors of thedisplay for the other person and the display for the driver stand out.In this way, the display for the other person and the display for thedriver appear to emerge, and thus, visibility is improved.

In the above embodiment, the necessity of the image-drawing operation inthe emergency mode is determined from a relationship between thedistance from the own vehicle to the pedestrian and the braking distanceof the own vehicle. However, as a condition for performing theimage-drawing operation in the emergency mode, suitable conditions suchas when the own vehicle accelerates or suddenly decelerates, when thepedestrian jumps ahead of the own vehicle and when the distance to theintersection is less than a predetermined value may be adopted.

In the image-drawing operation in the emergency mode, the blinking ofthe display for the other person and the display for the driver do notneed to be synchronized. From the viewpoint of calling attention toother person, the blinking frequency of the display for the other personmay be higher than that of the display for the driver.

In the image-drawing operation in the emergency mode, the brightness ofthe display for the other person and the display for the driver does notneed to be the same. From the viewpoint of calling attention to otherperson, the display for the other person may be brighter than thedisplay for the driver.

In the image-drawing operation in the emergency mode, the change of thedisplay mode is not limited to the change of blinking frequency of thedisplay. As the emergency increases, the brightness of the display maybe increased or the color sense of the display may be changed.

The display for the other person and the display for the driverdescribed with reference to FIGS. 8A to 9 do not need to be continuedthroughout the execution period of the image-drawing operation by theimage-drawing device 8. It is also possible to adopt a configuration inwhich only a spotlight-like display is drawn on the road 104 when thedistance to the intersection 103 is equal to or greater than apredetermined value and a display of the form illustrated in FIGS. 8A to9 is drawn when the distance to the intersection 103 is less than thepredetermined value.

In the above embodiment, the display for the other person and thedisplay for the driver are drawn on the road in the travelling directionof the own vehicle C. However, when the own vehicle data acquisitionunit 83 detects, through the steering angle sensor 61 or the directionindicator detection sensor 6, that the own vehicle C performs its coursechange, at least one of the display for the other person and the displayfor the driver can be drawn on the road after the course change.

The display for the other person and the display for the driver may beindividually stopped at the discretion of the driver. For example, aswitch for releasing the image-drawing operation can be provided in theown vehicle. Alternatively, it is also possible to adopt a configurationin which the image-drawing operation is automatically canceled when apassing operation, a winker operation, a hazard lamp operation, aswitching operation to a first speed in a manual transmission vehicle oran off operation of a first speed switch, or the like is performed.

The whole of the road surface image-drawing system 7 is not necessarilyprovided in the headlamp device 1. For example, as shown in FIG. 10, theimage-drawing device 8 can include a head up display (HUD) device 73. Asshown in FIG. 4, the HUD device 73 can be connected to the lamp ECU 51.The HUD device 73 is configured to project the display MM (an example ofthe first display) for the driver on the windshield W (an example of thefirst position) of the own vehicle C. In the present specification, anoperation of projecting a predetermined display on an object is alsoconsidered as an example of the “image-drawing”.

According to this configuration, the driver of the own vehicle C canvisually recognize the display MM for the driver in a state of beingoverlaid on the front landscape seen through the windshield W.Therefore, the driver of the own vehicle C can visually recognize thedisplay MM for the driver in a reliable manner, regardless of the stateof the road surface.

The road surface image-drawing system 7 may be provided in any one ofthe left and right headlamp devices. When the road surface image-drawingsystem 7 is provided in each of the left and right headlamp devices, theroad surface image-drawing systems 7 on the left and right sides canperform different image-drawing operations. For example, as shown inFIG. 9, when a pedestrian is present on the left side of theintersection 103 or is supposed to be on the left side, the characterM04 may be drawn by the road surface image-drawing system 7 provided inthe left headlamp device and the mark MM2 may be drawn by the roadsurface image-drawing system 7 provided in the right headlamp device. Onthe contrary, when a pedestrian is present on the right side of theintersection 103 or is supposed to be on the right side, the characterM04 may be drawn by the road surface image-drawing system 7 provided inthe right headlamp device and the mark MM2 may be drawn by the roadsurface image-drawing system 7 provided in the left headlamp device.

The whole of the road surface image-drawing system 7 may be disposedoutside the headlamp device 1. For example, the road surfaceimage-drawing system 7 can be disposed on a roof of the own vehicle suchthat an emission direction of the output light B2 is directed forward.

The configuration of the laser light source unit 10 can be appropriatelychanged in accordance with the specifications of the headlamp device 1.Instead of the first light source 15, the second light source 16 and thethird light source 17 for emitting light of three colors in the aboveembodiment, a single light source for emitting a white light can beused. Alternatively, a configuration that a white light is emittedthrough excitation by making a blue laser light incident on a yellowphosphor may be adopted. Further, a fourth light source for emitting anorange light may be added. Meanwhile, the first light source 15, thesecond light source 16 and the third light source 17 may be laser lightsources other than laser diodes.

Instead of the MEMS mechanism, a scanning optical system such as agalvanometer mirror or a DMMD (Digital Micro Mirror Device) can beadopted as the scanning mechanism 11. The scanning performed by thescanning mechanism 11 is not limited to the example shown in FIG. 5. Forexample, a configuration that the scanning point is verticallyreciprocated in the scanning area SA while shifting its position in thehorizontal direction can be adopted.

The function of at least one of the laser light source control unit 81,the actuator control unit 82, the own vehicle data acquisition unit 83,the travelling environment determination unit 84, the other vehicle dataacquisition unit 85, the other vehicle determination unit 86, thepedestrian data acquisition unit 87, the pedestrian determination unit88, the intersection data acquisition unit 89, the intersectiondetermination unit 90, the pedestrian risk determination unit 91 and thedisplay content determination unit 92 in the lamp ECU 51 is realized bya software executed by the cooperation of the lamp ECU 51, the ROM 52and the RAM 53. However, the function of at least one of the laser lightsource control unit 81, the actuator control unit 82, the own vehicledata acquisition unit 83, the travelling environment determination unit84, the other vehicle data acquisition unit 85, the other vehicledetermination unit 86, the pedestrian data acquisition unit 87, thepedestrian determination unit 88, the intersection data acquisition unit89, the intersection determination unit 90, the pedestrian riskdetermination unit 91 and the display content determination unit 92 canbe realized by a hardware such as a circuit element or a combination ofa hardware and a software.

The contents of Japanese Patent Application No. 2014-181881 filed onSep. 8, 2014 are incorporated as a pan of the description of the presentapplication.

1. A display system for a vehicle configured to display information at aplurality of places, wherein the display system is mounted on thevehicle, the display system is configured to display a first display ona windshield of the vehicle for a driver of the vehicle and to display asecond display on a road for a person outside the vehicle other than thedriver, and the information displayed in the plurality of places arerelated to each other.